Wholly aromatic polyester resins have long been known. For instance, 4-hydroxybenzoic acid homopolymer and copolymers have been provided in the past and are commercially available. Such polymers commonly are crystalline in nature, relatively high melting or possess a decomposition temperature which is below the melting point, and when molten frequently exhibit an isotropic melt phase. Molding techniques such as compression molding or sintering may be utilized with such materials. Representative publications which discuss these wholly aromatic polyesters include: (a) Polyesters of Hydroxybenzoic Acids, by Russell Gilkey and John R. Caldwell, J. of Applied Polymer Sci., Vol. II, Pages 198 to 202 (1959), (b) Polyarylates (Polyesters From Aromatic Dicarboxylic Acids and Bisphenols), by G. Bier, Polymer, Vol. 15, Pages 527 to 535 (August 1974), (c) Aromatic Polyester Plastics, by S. G. Cottis, Modern Plastics, Pages 62 and 63 (July 1975), and (d) Poly(p-Oxybenzoyl Systems): Homopolymer for Coatings: Copolymers for Compression and Injection Molding, by Roger S. Storm and Steve G. Cottis, Coatings Plast. Preprint, Vol. 34, No. 1, Pages 194 to 197 (April 1974). See also, U.S. Pat. Nos. 3,036,990; 3,039,994; 3,169,121; 3,321,437; 3,553,167; 3,637,595; 3,651,014; 3,662,052; 3,668,300; 3,723,388; 3,759,870; 3,767,621; 3,773,858; 3,787,370; 3,790,528; 3,829,406; 3,857,814; 3,884,876; 3,890,256; 3,974,250; and 3,975,487; U.K. patent application No. 2,058,102A.
In U.S. Pat. No. 3,637,595 a relatively high melting polymer is disclosed which may comprise 4-oxybenzoyl moiety, dioxyaryl moiety (e.g. p,p'-dioxybiphenylene), and terephthaloyl moiety.
It has been disclosed that certain polyesters may be formed which exhibit melt anisotropy. See, for instance, (a) Polyester X7G-A Self Reinforced Thermoplastic, by W. J. Jackson, Jr., H. F. Kuhfuss, and T. F. Gray, Jr., 30th Anniversary Technical Conference, 1975 Reinforced Plastics Composites Institute, The Society of the Plastics Industry, Inc., Section 17-D, Pages 1-4; (b) Belgian Pat. Nos. 828,935 and 828,936; (c) Dutch Pat. No. 7505551; (d) West German Nos. 2520819, 2520820, 2722120, 2834535, 2834536 and 2834537; (e) Japanese Nos. 43-223; 2132-116; 3017-692; and 3021-293; (f) U.S. Pat. Nos. 3,991,013; 3,991,014; 4,057,597; 4,066,620; 4,067,852; 4,075,262; 4,083,829; 4,093,595; 4,118,372; 4,130,545; 4,130,702; 4,146,702; 4,153,779; 4,156,070; 4,159,365; 4,161,470; 4,169,933; 4,181,792; 4,183,895; 4,184,996; 4,188,476; 4,201,856; 4,219,461; 4,224,433; 4,226,970; 4,230,817; 4,232,143; 4,232,144; 4,238,598; 4,238,599; 4,238,600; 4,242,496; 4,245,082; 4,245,084; 4,247,514; 4,256,624; 4,265,802; 4,267,304; 4,269,965; 4,272,625; 4,279,803; 4,284,757; 4,285,852; 4,287,332; 4,294,955; 4,299,756; 4,311,824; 4,314,073; 4,318,841; 4,318,842; 4,332,759; 4,333,907; 4,335,232; 4,337,191; 4,339,375; 4,341,688; 4,346,208; 4,347,349; 4,351,917; 4,351,918; 4,355,132; 4,355,133; 4,355,134; 4,359,569; 4,360,658; 4,362,777; 4,370,466; 4,371,660; 4,374,288; and 4,375,530; (g) U.K. Application No. 2,002,404; (h) British Pat. No. 1,568,541; and (i) European patent application Nos. 24,499 and 45,499.
Representative disclosures of anisotropic melt forming polyesters, poly(ester-amides), or poly(ester-carbonates) which may include 6-oxy-2-naphthoyl moiety are present in U.S. Pat. Nos. 4,161,470; 4,219,461; 4,256,624; 4,279,803; 4,299,756; 4,318,841; 4,318,842; 4,330,457; 4,337,190; 4,347,349; 4,351,917; 4,351,918; 4,355,133; 4,359,569; 4,362,777; 4,371,660; and 4,375,530.
In U.S. Pat. No. 4,219,461 a polyester is disclosed which comprises substantial concentrations of 6-oxy-2-naphthoyl and 4-oxybenzoyl moieties, and symmetrical dioxyaryl and symmetrical dicarboxyaryl moieties. The 6-oxy-2-naphthoyl moieties are provided in a concentration of approximately 20 to 40 mole percent in all instances. Also while a 4,4'-dioxybiphenyl moiety is illustrated, no polymer is exemplified which incorporates this moiety. In the Example the polymer exhibited a substantially lower modulus than that commonly observed with the specifically defined polymer of the present invention.
In U.S. Pat. No. 4,299,756 a polyester is disclosed which comprises 6-oxy-2-naphthoyl moiety, 3-phenyl-4-oxybenzoyl or 2-phenyl-4-oxybenzoyl moiety, 1,3-dioxyphenylene moiety, and terephthaloyl moiety.
In U.S. Pat. No. 4,318,841 a polyester is disclosed which comprises 6-oxy-2-naphthoyl moiety, 4-oxybenzoyl moiety, the non-symmetrical 1,3-dioxyphenylene moiety, and terephthaloyl moiety.
In U.S. Pat. No. 4,370,466 a polyester is disclosed which comprises about 2.5 to 15 mole percent of 6-oxy-2-naphthoyl moiety, about 40 to 70 mole percent of 4-oxybenzoyl moiety, at least about 10 mole percent of 1,3-dioxyphenylene moiety, and at least 10 mole percent of isophthaloyl moiety. The polymer there reported is indicated to exhibit a substantially lower modulus than that commonly observed with the specifically defined polymer of the present invention.
It is an object of the present invention to provide a novel melt processable polyester which forms a highly tractable anisotropic melt phase.
It is an object of the present invention to provide a novel melt processable polyester which forms an anisotropic melt phase and which has been found to be capable of melt extrusion to form quality high performance fibers, films, three-dimensional molded articles, etc.
It is an object of the present invention to provide a novel melt processable polyester which forms a melt phase below approximately 400.degree. C. in the substantial absence of polymer degradation unlike many polymers which include a relatively high concentration of 4-oxybenzoyl moiety.
It is a further object of the present invention to provide a novel melt processable polyester which can commonly be prepared on a more economical basis than that claimed in U.S. Pat. No. 4,219,461 since it includes 6-oxy-2-naphthoyl moiety in a relatively low concentration, and which has been found to be capable of forming products which exhibit an unusually high modulus in combination with other desirable properties (e.g. strength and retention of properties at elevated temperatures).
These and other objects, as well as the scope, nature and utilization of the invention will be apparent to those skilled in the art from the following detailed description.